Adapted from Martha Stewart's Chocolate Chunk Cookies
(I prefer baking in grams, and I decreased the amount of sugar because I used milk chocolates instead of semisweet chocolates)

340g all-purpose flour
1tsp baking soda
1tsp salt
226g unsalted butter, slightly firm and cut into chunks
170g packed brown sugar
75g granulated sugar
2 eggs
2tsp pure vanilla extract
2/3 cup sour cream
150g milk chocolates,chopped

Preheat oven to 176C. Cream butter and sugars until light and fluffy. Whisk the remaining dry ingredients in another bowl and set aside. Add eggs and vanilla gradually to the butter mixture until combined. Add sour cream. Then add flour mixture. Stop the mixer until combined and fold in chocolates. Chill until the batter is firm, around 3hours.

Drop cookie dough at least 2inches apart on baking sheet. Bake and rotate sheets halfway through, until the sides are golden brown but still soft to the touch, 15-16minutes. (Chilled dough will take longer)